Question

what is difference between working of geyser and working on geyser

Answer 1

working Of gyser means ur asked to describe how the gyser works
and working on gyser means a technician working on a problematic gyser

Answer 2

working of geyser means  the water boils, the resulting pressure forces a super heated column of steam and water to the surface through the geyser's internal plumbing. but working on geysers means an object working with the support of geyser